Crucible sling



M. H. BERNS CRUCIBLE SLING Sept. 5, 1967 Filed July 27, 1965 I BIZENTOR.

ATTORNEYS.

United States, Patent 3,339,965 CRUCIBLE SLING Milton H. Berns, Hamburg,N.Y., assignor, by mesne assignments, to Ferro Corporation, Cleveland,Ohio, a corporation of Ohio Filed July 27, 1965, Ser. No. 475,167 3Claims. (Cl. 294-74) This invention relates to an improved method ofhandling graphite and similar crucibles and a device therefor so thatthey can be more easily and safely moved about and/or inserted in placein packing cases for shipment and in furnaces preparatory to use.

Such crucibles are old in the art, being made for example as describedin Patents Nos. 1,356,939, 1,458,724, 1,458,726, and 1,479,107, out of amixture of graphite and silicon carbide held together by a binder ofcarbonized tar or pitch with a protective glaze such as that describedin Patent No. 1,828,767. Other crucibles are made of clay bondedgraphite, vitrified by suitable firing. They are in all cases relativelydelicate and subject to serious damage by chipping or other breakageduring handling. Originally American crucibles were made barrel shapedwith an expanded bilge so that they were easily handled with finger-liketongs which clasped them firmly for lifting.

As the art progressed however, the crucibles became more cylindrical oreven bowl shaped and very much larger. In many cases very large built-onlips are permanently attached at the upper edge. All these changes madehandling more difficult, while the greatly increased weight of thecrucible or pot or bowl made handling more dangerous and difficult.Crucible diameters came to exneed 30 with heights of almost three feet.Such crucibles weighed up to 1500 lbs.'Bowls are even larger andheavier.

less in diameter sothat care has to be used to prevent accidental upsetswith serious damage to the article.

To move such crucibles from the manufacturing area to the packing room,they were dragged or rolled up boards onto small trucks which moved themcarefully to the shipping room where they were similarly taken from thetrucks and in due time rolled onto a cushioning base of straw or similarpacking on a base of a crate and the sides of the crate built up aroundthem after which the surrounding space in the crate was stuffed withmore straw to protect them during shipping.

Before opening them in the customers plant, these crates were taken asnear as possible to the place the crucible was to be installed, thenopened up and the crucible tilted over by an operator until it rested onits side on the projecting forks of a lift truck. This truck then fedthe crucible, base first, into the open mouth of a tilting furnace whichhad been tipped to receive it. By careful jiggling and a certain amountof luck, the crucible was there adjusted in position to rest on oragainst its supporting members after the fork was withdrawn.

In the case of bowls where the furnace was not tiltable, a series ofropes might be tied around the side of the bowl and then over strongwooden timbers which were lifted by several workmen to move the bowlinto place in the furnace, and the ropes then removed.

The use of these various clumsy and uncertain devices is obviated by myinvention in which I apply to the crucible at as early a stage as it isknown to be sound, an inexpensive, closely fitting permanent sling ofcombustible material whereby the crucible can be lifted vertically andmoved about as may be required while so supported and thereafterdeposited accurately in any desired position for further attention oruse.

For example, I may use a lift truck with an overhead hoisting mechanismto pick the crucible directly from the I he underneath supporting areasare often considerably inspection floor and while suspended from aboveconvey it quickly to the shipping room where the crucible can be setdirectly downward into the center of a cylindrical packing container ona pad of straw packing and additional packing stuffed around it. I findsuch containers cheaper to provide and easier to move about than the oldtype with built up rectangular sides and my new device is ideallyadapted for use with them.

When the time comes to put the crucible in the furnace, it is liftedvertically out of the packing container by a suitable hoist and setdirectly down, accurately in position in the furnace. My handling slingstays in position during all thi and is left on the crucible until itburns away after the furnace is put in service.

My device is exceedingly simple, consisting of a plurality (three orfour give excellent results) of combustible fabric straps such as nylonwebbing which support the crucible and extend up its sides and acrossthe top to a central fastening which holds them tautly in place andserves as a support by which the whole may be lifted by a hook.

The accompanying figures illustrate various forms and aspects of myinvention.

FIG. 1 shows a side view of a crucible with one my slings on it inposition to be picked up by a hook above it.

' FIG. 2 shows a cross section of a pair of rings with straps aroundthem which constitute one simple form of holding the straps securely inplace and providing a fitting for lifting the crucible.

FIG. 3 shows an alternative form on a bowl.

-FIG. 4 shows an alternative method of assembling straps to go under acrucible before they extend up its sides.

In general in the variou figures similar numerals designate similarmembers where the meaning seems clear. In FIG. 1 the crucible 1 hasrunning down its-outside face a strap 2 of nylon webbing which passesdiametrically across under the bottom of the crucible and up its backside. A similar strap 3 is positioned 90 around the crucible, the straps-2 and 3 crossing each other under the bottom of the crucible.

Both straps 2 and 3 are brought in over the top edge of the crucible toa central fastening 6 where they are made taut and firmly secured by anysuitable means, such of my sling in place for example as the pair ofrings shown in FIG. 2. When it is desired to lift the crucible, hook 5on a hoisting device engages member 6 whereby the crucible may be raisedsafely. It is important that the various straps be drawn up relativelytight as otherwise they could slip sideways to an unbalanced position oreven slip off the crucible completely.

In FIG. 1 I show between the straps 2 and 3 and the bottom of thecrucible, but particularly at the sharper corners of the latter, aprotective pad 4 which may be of heavy, soft cardboard or other materialwhereby any tendency of the strap to cut into the crucible i minimized.Similar pads 5 are also shown protecting the upper edge of the cruciblewhere the straps cross it. The use of such protective pads is notstrictly essential, but their use is recommended at angular points ofcontact between the strap and the crucible as a safety measure which isinexpensive.

While the straps may be fastened to the upper holding member 6 by anysuitable means such as various buckles or staples, the device shown inFIG. 2 has been used with success and is easily applied. Here twosimilar steel rings 6a and 6b are provided. Each of these is perhaps 3to 5 inches in overall diameter and is made of inch diameter steel rodwelded to form a circular ring.

The strapping, here indicated as 3, is brought in over the top edge ofthe crucible and upward through the center of both rings as shown. It isthen turned down around the outside of the upper ring 612 and againbrought inside the lower ring 6a where it is inserted between this ringand the strap as it first turns up through this ring. The strap from theopposite side is similarly secured to the opposite side of the tworings. The loose ends 3a of the straps are then pulled up snug and therings can thereafter be dislodged only with difiiculty. Actually therings and straps thus secured are left permanently in place until thecrucible is ready to use, when the straps may be cut or burned away.

I have found relatively light webbing such as American Viscose Co.s Avisstrip which is 4 inch wide and has a breaking strength of 500 lbs.tensile to be well suited for slings of smaller crucibles weighing up to300 lbs. For heavier ones, I prefer nylon webbing of the type designatedas 10x which has a tensile strength of 2000 lbs. This I use in 1% inchwidth.

An alternative form of sling is shown in FIG. 3 in which I provide alower supporting strap 7 of similar nylon material stitched together toform a belt which surrounds the lower portion of the crucible or bowl ina region of decreased diameter. A protective pad 7a may be providedhere. The supporting straps 8 are firmly stitched to belt 7 at theirlower ends. At their upper ends, they pass over the edge of the cruciblewith similar protective pads and as in FIGS. 1 and 2 are secured to acentral holding and lifting device 6.

FIG. 4 illustrates another alternative sling method in which threesupporting nylon straps spaced 120 apart are sewed to a fabric disc 9which is placed under the bottom of the crucible before the straps areled out and up the sides of the crucible (not shown here).

The various devices shown are for purpose of illustration and furtheralternative forms and materials may be substituted within the scope ofthe appended claims. In general it is preferred that the supportingstraps be made of combustible material, of which nylon is an example,because the material can then be burned away when the crucible is put inservice without leaving a residue which requires removal to avoidobstructing the furnace or contaminating the metal being processed.

I claim:

1. A readily handled crucible assembly, comprising:

(a) a frangible crucible having a substantial percentage of carbon whichhas an open top defined by a substantially circular peripheral edge,

(b) a plurality of spaced longitudinally extending straps tightlyengaging the outside of said crucible and which have free end sectionspassing over said peripheral edge and across the open top of saidcrucible substantially in a fiat plane to engage and support at theirends a centrally disposed adjustable fastening means,

(c) said straps being made of combustible material,

(d) said fastening means being made of metal and permitting take-up onthe straps by pulling on the ends of said straps, whereby tensionadjustment and take-up for crucible size may be made by simply pullingon the free end of each of said straps, and

(e) said fastening mean and said straps are sufficiently taut and strongto permit grasping of said fastening means by a hoist assembly so thatthe entire crucible assembly may be lifted, transported and accuratelyinserted in a melting furnace.

2. A crucible assembly as set forth in claim 1, where- (a) saidfasteniing means comprises two superposed metal rings of the same size,and

(b) the strap ends are each passed under both rings, up along theinsides thereof, around the top and down the outside of the top ring, inbetween the top and bottom rings, and behind and under and out from thebottom ring between the bottom ring and the intermediate portion of thestrap which extends under the bottom ring.

3. crucible assembly as set forth in claim 1, where- (a) protective padscomposed of soft yieldable material are inserted between the said strapsand the crucible at angular points of contact of the straps with thecrucible.

References Cited UNITED STATES PATENTS 1,088,939 3/1914 Snee 294772,668,732 2/1954 Carlson 294 2,793,905 5/ 1957 Hillyer 294-74 3,120,2482/1964 Gregory 21417.6 X 3,120,403 2/ 1964 Molzan 29474 3,203,726 8/1965 Smith 29474 FOREIGN PATENTS 1,250,207 11/ 1960 France.

GERALD M. FORLENZA, Primary Examiner.

HUGO O. SCHULZ, Examiner. G. F. ABRAHAM, Assistant Examiner.

1. A READILY HANDLED CRUCIBLE ASSEMBLY, COMPRISING: (A) A FRANGIBLECRUCIBLE HAVING A SUBSTANTIAL PERCENTAGE OF CARBON WHICH HAS AN OPEN TOPDEFINED BY A SUBSTANTIALLY CIRCULAR PERIPHERAL EDGE, (B) A PLURALITY OFSPACED LONGITUDINALLY EXTENDING STRAPS TIGHTLY ENGAGING THE OUTSIDE OFSAID CRUCIBLE AND WHICH HAVE FREE END SECTIONS PASSING OVER SAIDPERIPHERAL EDGE AND ACROSS THE OPEN TOP OF SAID CRUCIBLE SUBSTANTIALLYIN A FLAT PLANE TO ENGAGE AND SUPPORT AT THEIR ENDS A CENTRALLY DISPOSEDADJUSTABLE FASTENING MEANS, (C) SAID STRAPS BEING MADE OF COMBUSTIBLEMATERIAL, (D) SAID FASTENING MEANS BEING MADE OF METAL AND PERMITTINGTAKE-UP ON THE STRAPS BY PULLING ON THE ENDS OF SAID STRAPS, WHEREBYTENSION ADJUSTMENT AND TAKE-UP FOR CRUCIBLE SIZE MAY BE MADE BY SIMPLYPULLING ON THE FREE END OF EACH OF SAID STRAPS, AND (E) SAID FASTENINGMEANS AND SAID STRAPS ARE SUFFICIENTLY TAUT AND STRONG TO PERMITGRASPING OF SAID FASTENING MEANS BY A HOIST ASSEMBLY SO THAT THE ENTIRECRUCIBLE ASSEMBLY MAY BE LIFTED, TRANSPORTED AND ACCURATELY INSERTED INA MELTING FURNACE.